Home › Neurology › NIHSS

NIH Stroke Scale (NIHSS)

The NIHSS quantifies acute stroke deficit across 15 items (total 0–42). 0 = no measurable deficit, 1–4 minor, 5–15 moderate, 16–20 moderate-to-severe, 21–42 severe stroke.

1a. Level of consciousness: 0 – Alert (0); 1 – Not alert, arousable by minor stimulation (1); 2 – Not alert, needs repeated or painful stimulation (2); 3 – Unresponsive or reflex responses only (3)
1b. LOC questions (month, age): 0 – Answers both correctly (0); 1 – Answers one correctly (1); 2 – Answers neither correctly (2)
1c. LOC commands (open/close eyes, grip/release): 0 – Performs both tasks (0); 1 – Performs one task (1); 2 – Performs neither task (2)
2. Best gaze: 0 – Normal (0); 1 – Partial gaze palsy (1); 2 – Forced deviation or total gaze paresis (2)
3. Visual fields: 0 – No visual loss (0); 1 – Partial hemianopia (1); 2 – Complete hemianopia (2); 3 – Bilateral hemianopia (blind incl. cortical blindness) (3)
4. Facial palsy: 0 – Normal symmetric movement (0); 1 – Minor paralysis (flattened nasolabial fold) (1); 2 – Partial paralysis (lower face) (2); 3 – Complete paralysis (upper and lower face) (3)
5a. Motor arm – left: 0 – No drift for 10 s (0); 1 – Drift, does not hit bed (1); 2 – Some effort against gravity (2); 3 – No effort against gravity, falls (3); 4 – No movement (4); UN – Amputation / joint fusion (not scored) (0)
5b. Motor arm – right: 0 – No drift for 10 s (0); 1 – Drift, does not hit bed (1); 2 – Some effort against gravity (2); 3 – No effort against gravity, falls (3); 4 – No movement (4); UN – Amputation / joint fusion (not scored) (0)
6a. Motor leg – left: 0 – No drift for 5 s (0); 1 – Drift, does not hit bed (1); 2 – Some effort against gravity (2); 3 – No effort against gravity, falls (3); 4 – No movement (4); UN – Amputation / joint fusion (not scored) (0)
6b. Motor leg – right: 0 – No drift for 5 s (0); 1 – Drift, does not hit bed (1); 2 – Some effort against gravity (2); 3 – No effort against gravity, falls (3); 4 – No movement (4); UN – Amputation / joint fusion (not scored) (0)
7. Limb ataxia: 0 – Absent (or cannot understand / paralysed) (0); 1 – Present in one limb (1); 2 – Present in two limbs (2)
8. Sensory: 0 – Normal (0); 1 – Mild-to-moderate sensory loss (1); 2 – Severe to total sensory loss (2)
9. Best language: 0 – No aphasia (0); 1 – Mild-to-moderate aphasia (1); 2 – Severe aphasia (2); 3 – Mute, global aphasia (3)
10. Dysarthria: 0 – Normal (0); 1 – Mild-to-moderate dysarthria (1); 2 – Severe dysarthria (unintelligible or mute) (2); UN – Intubated / physical barrier (not scored) (0)
11. Extinction and inattention (neglect): 0 – No abnormality (0); 1 – Inattention/extinction in one sensory modality (1); 2 – Profound hemi-inattention or in more than one modality (2)

—

Interpretation

Result	Meaning
0	No stroke symptoms
1–4	Minor stroke
5–15	Moderate stroke
16–20	Moderate-to-severe stroke
21–42	Severe stroke

Formula

Sum of 15 items: 1a LOC 0–3 · 1b questions 0–2 · 1c commands 0–2 · 2 gaze 0–2 · 3 visual 0–3 · 4 facial 0–3 · 5a/5b arms 0–4 each · 6a/6b legs 0–4 each · 7 ataxia 0–2 · 8 sensory 0–2 · 9 language 0–3 · 10 dysarthria 0–2 · 11 extinction 0–2. Max 42. UN items are not added.

Clinical pearls

Score what the patient does, not what you think they can do; record the first response and do not coach.
The NIHSS under-weights posterior circulation deficits (vertigo, gait ataxia, dysphagia): a low score does not exclude a disabling or large-vessel stroke.
Severity bands are conventional groupings; thrombolysis eligibility depends on whether the deficit is disabling, not on a fixed NIHSS cut-off.

Examples

nihss: drowsy 1a 1, 1b 1, 1c 0, gaze 1, visual 0, face 2, left arm 3, right arm 0, left leg 2, right leg 0, ataxia 0, sensory 1, language 0, dysarthria 1, neglect 1 NIH stroke scale for an alert patient with mild right facial droop and right arm drift, otherwise normal

FAQ

What NIHSS score indicates a severe stroke?

Scores of 21–42 are conventionally classified as severe; 16–20 moderate-to-severe; 5–15 moderate; 1–4 minor.

What is the maximum NIHSS score?

42. Items marked UN (amputation, intubation) are not scored.

Does NIHSS predict large vessel occlusion?

Higher scores (often ≥6) raise the probability of LVO, but no cut-off reliably excludes it; image when clinical suspicion exists.

Evidence

Brott T et al. Measurements of acute cerebral infarction: a clinical examination scale. Stroke 1989;20:864–70.

Neurology · Reviewed 2026-10-14 · Methodology